Quantum Key Distillation from Gaussian States by Gaussian Operations
Miguel Navascués, Joonwoo Bae, J. I. Cirac, Maciej Lewenstein, Anna Sanpera, Antonio Acín · Physical Review Letters · 2005
We study the secrecy properties of Gaussian states under Gaussian operations. Although such operations are useless for quantum distillation, we prove that it is possible to distill a secret key secure against any attack from sufficiently entangled Gaussian states with nonpositive partial transposition. Moreover, all such states allow for key distillation, when Eve is assumed to perform finite-size coherent attacks before the reconciliation process.